It is known to form a printed wiring board by the "additive process" in which a base material which has been suitably roughened is suitably activated and, at least in part, treated to electroless metal deposition. It is desired that the metal to base material adhesion be at suitably high levels so that delamination of the metal from the board is made appropriately difficult.
The use of organosilane compositions in forming additive printed wiring boards is not unknown. For example, U.S. Pat. No. 3,978,252 to M. S. Lombardo et al. discloses the treatment of an etched aluminum-clad laminate with silane compounds containing one lower alkyl amino substituted radical, rinsing of the treated substrate, activation, and electroless copper plating. The adhesion of copper to the substrate is said to be no more than about 10 pounds per inch. U.S. Pat. No. 4,897,118 to D. R. Ferrier et al. provides an insulating substrate with a resist to define areas where metallization is desired, the resist patterned substrate is then treated with a "conditioner" (which is preferably an organo-functional silane, which can include ureidoalkyl silane esters), adjuvant (preferably amine compounds), and deactivating agent. Rinsing of the treated board after application of conditioner and adjuvant, but before deactivating agent, is shown in the Examples contained in this patent. Thereafter, activation and electroless plating of metal onto the substrate is performed.
Recently, European Patent Publication No. 241,739 of C. R. Jones et al. has described application of a liquid or vaporous silicon compound to a dielectric substrate followed by treatment with oxygen plasma to, apparently, convert the silicon moieties on the substrate to silicon dioxide with etching away of the organic moieties contained between the silicon entities. Electroless deposition of metal (which may be followed by electrolytic deposition) can be used to treat the plasma treated substrate.
Organosilane compositions have also been used in regard to making metal-plastic laminates useful in fabrication of circuit board products by processes which differ from the above-described additive process in which an appropriately treated base material is activated and then electrolessly plated with metal. For example, U.S. Pat. No. 4,100,312 to M. S. Lombardo et al. applies an organic silicon compound to a sacrificial metal foil, dries the treated foil, and then laminates the treated foil to a plastic substrate. U.S. Pat. No. 4,499,152 to R. W. Green et al. vapor deposits metal on a carrier sheet, coats the metal with a metal oxide layer, treats the metal oxide layer with a coupling agent (e.g., an organo-functional silane), and laminates the composite to a substrate. The carrier sheet can then be removed. U.S. Pat. No. 4,902,556 to G. M. Benedikt et al. discloses treatment of a metal foil with silane and lamination of the treated foil to an epoxy prepreg, for example. A more recent patent, which happens to focus on the use of a ureidosilane bonding mixture containing a disilyl crosslinking agent is U.S. Pat. No. 5,073,456 to J. V. Palladino which discloses application of the bonding mixture to the surface of an oxide/hydroxide formed on copper circuitry formed on a dielectric support. The combination of support, copper, oxide-hydroxide, and bonding mixture is laminated to one or more similar laminates. Of similar teaching to the Palladino reference is European Patent Publication No. 310,010 which contains a wider disclosure of organosilane compounds without a disilyl crosslinking agent in an analogous lamination process.